Whose decision is it that our country uses the
standard system and not the metric system? I find
it confusing that almost every other country uses
the metric system except for the United States.
Why don't we? If our country ever did switch to
the metric system, who would be in charge of
confirming that change?

Question Date: 2009-11-12

Answer 1:

This seemingly innocuous issue is in fact
governed by an act of congress. Technically, we
did pass some legislation some decades ago which
required slow conversion to the metric system --
however, this was slowly changed in the ensuing
years to become almost non existent.

You
might wonder why? In several ways, this decision
is more costly and political than you might at
first believe. Along with the metric system of
weights and measures, comes a host of other
standards -- such as screw sizes, threading
requirements, gearing pitches and other machine
specific standards. Such standards have existed
since before the turn of the century in the (at
the time) most advanced countries in terms of
manufacturing and standards: these were the US and
Great Britain. Note Germany was known for cutting
tools and the famous Solingen Steels (with
inclusions of Tungsten Carbide-- but they didn't
know it then) but they were not big on mass
manufacturing with interchangeable parts-- a
concept pioneered by Ely Whitney and his
disciples. Also note that these countries were the
major holdouts of the Metric system...

Here
is why: re-tooling costs billions of dollars. It
is a boon for the countries that already use the
new standard and a bane for those who don't. A
second issue is the quality of the standard --
ASME standard screws are based on steels available
in the states during the mid 40's.At that time we
had most advanced steel production in the world.
The screws took advantage of the superior hardness
and tensile strength so that the standard for
high-end screws is lighter and smaller than their
metric counterparts -- a disparity that largely
remains true today.Similar issues occur in
standard gears, although such gears have largely
been replaced by modules. The current state of
affairs is that most US,Chinese and Japanese
companies have both sets of tooling in house and
most production is slowly moving to metric
standards and to newer joint standards that are
being developed to fill the gaps in the metric
machine standards.

There is a final issue --
that of measurement of the standards which must be
traceable to the originals. Because of recent
discoveries (quantum Hall effect and ion fountain
clocks) most of the standards (i.e. length,
voltage and such are now derived from others. Even
the speed of light is now a defined constant, not
a measured speed). One of the remaining constants
is the kilogram (which looses mass every time it
is handled). It is far easier and cheaper (and
more repeatable and accurate) to compare with the
American NIST standards than the international
ones. If you are interested in the current state
of defined standards and physical constants --
check out the APS (AmericanPhysical Society)
website for the paper they update every year on
physical constants.

Upshot is that it is a
bit more involved than replacing street signs
--which should have been done years ago -- if not
for the difficulty in addresses and surveying...

Answer 2:

Im with you; the United States is about 200
years behind the times in our system of
measurement.People around the world use the metric
system, but here in the US, most people, except
scientists, have resisted it. The short answer is
that Congress can make laws that tell businesses
and agencies to use the metric system. Executive
orders from the president can tell federal
agencies to use it. I found an interesting
article by David Smith of the Federal Highway
Administration

He gives a brief history of the struggle
to get the US on board with the metric system and
concludes that it will happen soon, but you will
notice that the article is dated 1995. Here we
are almost 15 years later, and were still buying
gallons of gas and driving miles of roadway.

There are some costs to converting industries,
changing signs, and such, but the longer we drag
our feet, the more that cost increases. In my
opinion, the reason were still on an outmoded
system is because many people are too lazy to
learn and use the new system. Politicians dont
want to be unpopular, so they choose their
battles, only making the majority unhappy when
they feel they have to. It is unfortunate because
the metric system is actually much easier to learn
and use. Teachers and students would be much
better off if American students did not have to
learn an old-fashioned, illogical system.
Switching to the metric system now would be a gift
to future generations of Americans.

The
Office of Weights and Measures also has a useful
document on the history of the Metric system in
America:

Changing the unit system would require a law,
which in turn would require the institution in the
United States that passes laws, namely, the
legislature: the House of Representatives, and the
Senate. Of course, the President would have to
*sign* such a bill before it could become law, but
the law would be written by Congress.

So why
don't we switch over to metric? President
Carter tried to push that - but the country - and
the rest of the government - wouldn't listen, and
as I said, a president alone doesn't have the
power to make that kind of change.